I'm having trouble picturing your layout. Is the stove going directly beneath the window? Is the window right at the corner? If the stove going in directly beneath the window, if so, is the back going against the exterior wall with the window or against the interior wall that is 90 degrees to the wall with the window? Is the stove going exactly in the corner or do you have countertop that makes an "L" with the stove just beyond the L? Are the ceilings 8 feet high? Maybe you have a galley style kitchen with the counters running perpendicular to a wall with a a doorway aat one end and a window next to it? I ask all this because my first thought was to ask why get a ductless hood (a "ventless vent" as it were) if you've got an exterior wall? Almost all wall-hung and cabinet-hung hoods can vent directly out the back through a wall. If the stove backs-up against an interior wall, it is easy to put an elbow on top of the vent hood and take it out the side wall -- unless, of course, that is where your window is. Do you condo association rules prohibit exterior venting hoods? As for"is it possible to mount "under cabinet" hoods NOT under a cabinet?" --- sure. Some under-cabinet hoods are constructed so to give an option of wall-mount or hanging undercabinet, but it will be easier (and more stable with less vibration) to hang most such hoods from a couple of upside down shelf-brackets -- or make a shelf and hang the hood from that. Putting a ventless hood 44" above the countertop strikes me as likely to be ineffective for grease. It is so far away from the stove and the fan power in most recirculating hoods is so low that it cannot capture much grease or steam. Most of the effluent will begoing to go on the walls, the window and out into the kitchen. Frankly, I think you would have more luck just putting a box fan in that window whenever you wanted to vent. Also, consider how high you'd have to reach to hit the switches on a recirculating hood that is placed that high. Think about reaching to the middle of the lintels over the doorways. Maybe not so big a deal if you are tall, but likely an annoyance nonetheless.

I think the reality is that many low or mid powered ducted hood fans is not enough for high power ranges. It looks like yours need something like 900 CFM or up. If you could not change the cooking style, I guess you need sacrifice something else. For example, is it possible to route the duct just under the ceiling to the window? You could warp the duct with bulkhead. It does not look the best, but you at least have the proper ventilation for your high-end range. Otherwise, you would find grease over the kitchen and maybe other rooms in no time. Having said that, I am not sure how well Vent-a-Hood Duct Free range hoods (http://www.ventahood.com/ductfree2.jsp) work. It looks like the technology used in those is a bit more sophisticated than the common peers. They are still for light cooking though. You may need a 42" if possible. ps: please read through this thread: http://ths.gardenweb.com/forums/load/appl/msg1214301011894.html about the vent-a-hood ars This post was edited by shimheric on Wed, Oct 22, 14 at 13:19

There's a thread about ductless hoods on the Appliances forum, first page right now, that you might find interesting.

Any hood that cannot be vented to the exterior requires a charcoal filter. The charcoal acts as an odor removing medium and will need changing regularly. Please put do not put your cooktop on an island, the whole "arrangement" is impractical and hazardous.